001/** 002 * Licensed to the Apache Software Foundation (ASF) under one or more 003 * contributor license agreements. See the NOTICE file distributed with 004 * this work for additional information regarding copyright ownership. 005 * The ASF licenses this file to You under the Apache License, Version 2.0 006 * (the "License"); you may not use this file except in compliance with 007 * the License. You may obtain a copy of the License at 008 * 009 * http://www.apache.org/licenses/LICENSE-2.0 010 * 011 * Unless required by applicable law or agreed to in writing, software 012 * distributed under the License is distributed on an "AS IS" BASIS, 013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 014 * See the License for the specific language governing permissions and 015 * limitations under the License. 016 */ 017package org.apache.camel.component.vm; 018 019import java.util.HashMap; 020import java.util.Map; 021import java.util.concurrent.BlockingQueue; 022import java.util.concurrent.atomic.AtomicInteger; 023 024import org.apache.camel.Endpoint; 025import org.apache.camel.component.seda.QueueReference; 026import org.apache.camel.component.seda.SedaComponent; 027import org.apache.camel.component.seda.SedaEndpoint; 028 029/** 030 * An implementation of the <a href="http://camel.apache.org/vm.html">VM components</a> 031 * for asynchronous SEDA exchanges on a {@link BlockingQueue} within the classloader tree containing 032 * the camel-core.jar. i.e. to handle communicating across CamelContext instances and possibly across 033 * web application contexts, providing that camel-core.jar is on the system classpath. 034 * 035 * @version 036 */ 037public class VmComponent extends SedaComponent { 038 protected static final Map<String, QueueReference> QUEUES = new HashMap<String, QueueReference>(); 039 protected static final Map<String, SedaEndpoint> ENDPOINTS = new HashMap<String, SedaEndpoint>(); 040 private static final AtomicInteger START_COUNTER = new AtomicInteger(); 041 042 @Override 043 public Map<String, QueueReference> getQueues() { 044 return QUEUES; 045 } 046 047 @Override 048 public QueueReference getQueueReference(String key) { 049 return QUEUES.get(key); 050 } 051 052 @Override 053 protected void doStart() throws Exception { 054 super.doStart(); 055 START_COUNTER.incrementAndGet(); 056 } 057 058 @Override 059 protected void doStop() throws Exception { 060 if (START_COUNTER.decrementAndGet() <= 0) { 061 // clear queues when no more vm components in use 062 getQueues().clear(); 063 // also clear endpoints 064 ENDPOINTS.clear(); 065 } 066 } 067 068 @Override 069 protected Endpoint createEndpoint(String uri, String remaining, Map<String, Object> parameters) throws Exception { 070 if (ENDPOINTS.containsKey(uri)) { 071 return ENDPOINTS.get(uri); 072 } 073 074 SedaEndpoint answer = (SedaEndpoint) super.createEndpoint(uri, remaining, parameters); 075 076 ENDPOINTS.put(uri, answer); 077 return answer; 078 } 079}